Method and apparatus for the straightening of the wefts of woven textile fabrics



June 3, 1947. c, NlELD 2,421,575

METHOD AND APPARATUS FOR THE STRAIGHTENING OF THE WEFTS OF,WOVEN TEXTILE FABRICS Filed April 27, 1944 2 Sheets-Sheet l Inventor Attorney J June 3, 1947. c. NIELD 2,421,575

. METHOD AND APPARATUS FOR THE STRAIGHTENING OF THE WEFTS OF wovEN TEXTILE FABRICS Filed April 27, 1944 T 2 Sheets-Sheet 2 Inventor 1672;? gar/(den A zkld 031E;

Attorney:

Patented June 3, 1947 ENT OFFICE Ma'Tnoo- AND Arr'mm'rrisv For: THE 'STRAIGHTENING on THE war'rs F WOVEN TEXTILE FABRICS Leslie Camden'Nield, Glossop, England, assignor -toTootal Broadhurst Lee Company Limited,

Manchester, England, a British company Application April 27, 1944, Serial No. 533,006

In Great Britain April 27, 1943 Claims. (Cl. 26-65) The weft threads ofa' woven fabric should be at right angles to the warp threads but in the processing of such fabrics the relative positions of such threads may be distorted and it is often necessary to provide means of correcting this distortion. Various means are known for doing this but these methods are usually manually operated. In many typ s of fabric it is difficult or impossible to see by visual inspection whether the weft threads are in the correct relative position. It is therefore very advantageous to have a mechanical means of detecting when the weft threads of a fabric are not at right-angles to the warp threads, which mechanical means may be made to operate apparatus for correcting the fault.

The present invention relates to an improved method and apparatus for determining when the weft threads are not truly at right-angles to the warp threads and for straightening them.

According to the present invention the selvedges of a web which is being continuously displaced are engaged obliquely tothe line of run of the web, the consequent lateral deflection of the web caused by said oblique engagement whenever the weft threads lie other than at right angles to the run of the web operating a weft straightening device.

Oneform of apparatus for carrying out the invention comprisestwo pairs'of rollers, each pair engaging one selvedge of the fabric web running freely past said rollers, means being provided to rotate said rollers at different peripheral speeds whenever a lateral deflection of'a'selvedge edge of the web occurs due to an unbalanced pull of said rollers, as will occur when the weft lies along a lne other than parallel to the line joining the median points of said pairs of rollers.

One form of construction according to this invention is shown in the accompanying drawings, in which: I

Figure 1 is a side elevation of a machine for detecting and rectifying weft unstraightness in a fabric web,

Figure 2 is a front view of the machine shown in Figure 1,

Figure 3 is a conventionalized diagram of the control and driving means for the floating element of the differential gear in the machine, with the drivin means shown in plan view,

Figure 4 is a diagram showing, in exaggerated form, displacementsiai a fabric when the, weft threads are unstraight and a lateral pull is applied to the edges, and

Figure 5 is an enlarged view of one of the d ferential gears shown in Figure 2.

The moving web or band of woven textile masuch supply of fabric or from any previous apparatus to the machine in such a way that it shall pass over, through or between any suitable apparatus which shall ensure the web travelling in a predisposed path, one preferred type being known as the Foxwell fabric positioners and are marked 2 on Figure 1. Thereafter the cloth shall pass over the horizontal guide roller 3 and thence to the control and straightening heads 4.

After leaving the nip roller heads 4, the web I is carried vertically downward and then under roller l8, which is carried by arms l8a pivoted on shaft I81) and counterbalanced by the weights l9, as shown in Figure 1. In Figure 2, the upward draft of the web I is cut away to show driven rollers l6 and I1. The web then passes over roller 20 to the next piece of apparatus by which it may be required to be treated.

The control and straightening heads 4 consist of two pairs of nip rollers l6 and I! (the free member of pair I6 being designated I6) one pair being disposed on either selvedge of the web, the axes of one pair of said nip rollers lying at an angle to the axes of the other pair of nip rollers. This angle can be varied at will about the axis of a shaft Ila when and if required. The disposition of these nip rollers can be seen from Figures 2 and 4.

These nip rollers are driven by suitable mechanism so that either one can be driven at a different speed than the other.

The aforesaid driving mechanism can be arranged as follows. Referring to Fig. 2, the driving shaft 5 is rotated by some prime mover or from suitably driven apparatus (not shown) disposed either before the weft straightening apparatus or following it.

Disposed on either side of the machine are two differential epicyclic gear boxes 6, an enlarged view of one of which is shown in Figure 5. The prime gear wheels 1 of the two differentials are rotated from the shaft 5 through keys which can slide in a long keyway (not shown) in shaft 5. As the same general arrangement is provided at each differential gearing, only one will be described in detail.

In the normal way, the drive is transmitted through the gear wheels 8 and 9 keyed on to shaft 38 rotatable in bearings carried by a worm wheel 38 to gear wheel l0 rotatably mounted on shaft 5. The train of gear wheels I, 8, 9, and in has a speed-reducing ratio of say 1.5:1. Fixed to the gear wheel [0 is a sprocket II, which engages a chain Ha to drive sprocket l2. which is keyed to a shaft l3 at the opposite end of which is a double mitre gear M to allow the change oi angle of the nip roller head 4: the middle mitre gear being ccaxial with the axis Ma about which the head 4 can move. The ratio of the chain drive H, I la, i2 is such that it has a speeding-up ratio the inverse of that in the compound train of gears, namely, 1:1.5. (This is onlyfor ease in working outshaft speeds relative to cloth speeds.) The last wheel of the double mitre gear I4 is fixed on'the shaft i5 which carries the driven member of the nip rollers l6 or H. v

The control of the speed of the nip rollers "is achieved from the two fingers 2 l,which are disposed (Fig. 2) at opposite edges'o'fthe web, each a small distance outside the general'run of'the fabric. these fingers provoke a change of speed of the corresponding rollersfia'lt will beunderstood, that identical sets of apparatus are providedfor each finger 2| and its associated parts, but onlycne will be described in detaiL. 1

-" When an age of thecloth web I is deflected laterally. and moved outwardinto contact with a finger 2-i,-this finger (Fig, 3) moves and closes the contacts 22 inthe switch box 23, and current is caused to flow in the solenoid-24, which pulls the pole piece 25 against the solenoid core frame 26 and into the position shown in Fig. 3., This movement of the pole piece 25 pushes the sliding tube 2'! against the thrust race 28 which in turn acts to push the clutch disc 29, engaged by a sliding key in shaft 30, into contact with the clutch lining 3i attached to the chain sprocket 32. The shaft 5 has a spiral gear 33 engaged with a spiral gear 34 on the shaft 30 sothat the latter is continuously rotated and acts, when the clutch 29-3l is engaged, to drive the chain sprocket 32 so that the chain 39 turns the chain sprocket 40 and therewith the shaft 4i carrying the worm 35. This worm 35 (Fig. 5) then rotates the worm wheel 36 which carries the shafts 38 of the differential gears, and thereby introducesa further component of motion so that, for example, the speed of the associated nip rollers is reduced, and the movement of the corresponding edge of the web is. retarded and thereby the weft threads are straightened, that is, brought to lie along lines normal to the direction of feeding of the web. Since this is produced by the relative speeds ofthe nip rollers at the two edges, it is obvious that a like result is attained by'causing the worm wheel 36 of the other diiferential to rotate and cause the speed of the associated nip rollers to be increased. threads passing the nip rollers When the weft are again at right angles to the direction of movement of the web, the lateral deflection or outward movement ceases, and the web now runs within the parallel limits established by the fingers 2i, and between these fingers without touching either. Hence the contacts 22 are broken at each side, the solenoids 24 are deenergized, the clutches 29-3! are open, and shafts 4| are at a standstill. The worm wheels 36 are at a standstill, and the nip rollers are again driven at the same speed.

The cloth positioner 2 and the straightening heads 4 together with the mechanism for driving them are arranged to slide on the guide bars 31 to accommodate various widths of fabric. The keyed engagements with shafts 5 permits such adjustment while assuring continuous drive.

The diagram of Figure 4. shows the displacement of the warp and weft threads as the cloth When the web I encounters eitherof 2|, electrical contacts are closed to;

I median points of the obliquely disposed rollers I6 seen that the selvedge on the web will move outwards more than the lefthand side and as a result there is more width of cloth in that nip, so it follows that nip rollers ll and I1, then the pull of these rollers becomes unbalanced, the nip rollers l1 pulling the fabric outwards more than the nip rollers l6 because the former are pulling more nearly parallel to the weft threads than the latter. Therefore it can be the right hand side of will, exert a still greater pull in their direction than nip rollers 16; hence the contact finger 2! adjacent to the rollers I! will be the one which will be operated'to effect directly or indirectly the displacement of the floating element of the differential gear in the particular arrangement described with reference to Figures 1 to 3, thus causing either a smeding up of the rollers H5 or a retardationof the rollers II, when rollers IE will exert a greater pull in the opposite direction which will vrestore the position of the finger to normal, when the sequence will repeat itself until the weft threads are very nearly at right-angles to the warp threads.

The operation of the differential gears may be carried out by other means than the electrical method previously described such as air or other fluid operating a diaphragm or piston to apply pressure to the friction clutch, or again a magnetic clutch may be used. In certain cases it may be desirable to use a small prime mover which may be started and stopped by operation of the selvedge contact fingers through relays or other servo mechanism.

It may also be desirable to dispense with differential gears and use a double chain drive alongside sprockets and I2 with a different ratio to give the speed change of the nip rollers in which case a double clutch of a sensitive type could be used, again operated by the fingers 2| through suitable servo mechanism.

It may also be desirable to use other forms of stretching heads in place of the nip roller heads 4, such as a short chain passing round a pair of chain wheels with either pins or some other apparatus to hold the web, these chains to be pivoted at one end so that a spring could be used to pull the chains out and so operate the fingers.

The counterbalanced roller pivot shaft l8 can be used to operate a control for automatic speed synchronisation of the weft straightening apparatus or other apparatus to some other following or preceding apparatus.

Instead of varying the peripheral speeds of the two sets of nip rollers relatively to one another, either by speeding one set up or by slowing one set down, or by both, the contact finger may operate any auxiliary known form of weft straightening device such as a pair of rollers over which the fabric web is passed, the angle of which relatively to the warp direction being varied by the control.

Instead of a mechanical control by spades or weft fingers 2|, any other known control arrangement operated by a displacement of the selvedge edge from a predetermined path may be used, such as a photo-electric cell arrangement.

oppositely to one another and applied along-aline normal to the direction of displacement of the web, and using the movement outwards of" either one or other edge 01' this web-outside one of said limits which will occur whenever the s'aid pull on the web no longer coincides with the direction of the weft threads ,to; ;operate,,weft,

straightening means to efiect movement of said edges at differential speeds while" maintaining applied the aforesaid pulling forces." I Y 2. A device for straightening the weft threads of a textile web comprising means to constrain thee'd gesof the web to move within predcter: mined parallel limits, two pairs'ofnip rollers on axes oblique to the movement. of the cloth and continuously engaging the edges of the web, individual driving means for said nip :rollers, and means controlled by the-movement outward of part of either edge of the web outside said predetermined limits whentheweftlies along a line other than parallelto the line joining the median points of said pairs of rollers. and effective to operate the drives for' the'pairsof rollers whereby to produce faster rotation ofthe pair of rollers its edges travelling at equal speeds in the warp direction, applying a pull to the web by equal and opposite forces acting along a line normal to the direction of movement of the web whereby to produce an outward deflection of one or the other edge of the web wherever the said pull no :longer coincides'with'the liir jiittion ofisald weft threads, andusing said outward deflection for selectively causing one edge of the web to move at a different rate than the other while the pulling forces are maintained applied and thereby 'effectstraightening ,z-Of the weft threads into parallelism with said line. q

5. Apparatus for straightening the weft threads of a, clflth web, comprising a frame past which the cloth maybe advanced in the general direction' of the warp threads, two oppositely and obliquely positioned pairs of nip rollers rotatively mounted on the frame and individual variable speed means for driving the same, said rollers and driving means being positioned and arranged to act continuously upon the cloth at edge portions thereof spaced at right angles to the said direction of advancement and to establish forces at each said portion for advancing the cloth and for causing said portions to move away from one another whereby a weft thread which lies other than parallel to the line joining the median points of the pairs of nip rollers is engaged by one pair of nip rollers before it is engaged by the other pair of nip rollers and thereby an outward move- I ment of one edge of the cloth is produced, and

at the sideopposite-tothat on which the move- I ment outwards occursthan at the other pair.

3. A device for straighteningthe weft threads of a textile web; comprising means: to constrain the edges of the web to-move witthin predetermined parallel limiw, two'pairs of nip rollers continuously engaging the edges of the web and mounted on axesoblique-to'the movement of the cloth, a pair of feelers disposed on opposite sides of said web andspaoed apart'a slightly greater distance than'th'e said parallel limits and disposed adjacent to said nip rollers, driving means for said rollers which include a differential gear couplingsaid' pairs of-nip rollers, each difierential gear having a floating element effective by its rotational displacement to control the rate of rotation'ofthe associated pair o1 nip rollers, and-means selectively operated by either one of said feelers to displace thefloating element of a corresponding diiferential gear whenever the web contacts with one or other of said feelers.

4. A method of straightening the weft threads of a cloth web, consisting in moving the web'with 55 detector means selectively responsive to the said outward movementand effective for. controlling the action of said variable speed driving means whereby to cause the advanced end of the obliquely-positioned weft thread to be relatively retarded.

I LESLIE CAMDENNIELD.

' REEERENCES ,crr'En The following references areof record in the file of this patent:

UNI'I'ED srrrns' PATENTS Great Britain 1913 

